Error while running test suite on Amazon EC2

[andrioni]

I'm not actually sure where this problem is happening, but it only happens on an EC2 box when targeting Sandy Bridge. If I recompile OpenBLAS to use Nehalem directly, I get rid of the warnings and the errors.

Why would a wrongly-configured BLAS make spawn.jl fail?

$ make testall
    JULIA test/all
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
OpenBLAS : Your OS does not support AVX instructions. OpenBLAS is using Nehalem kernels as a fallback, which may give poorer performance.
        From worker 3:       * linalg2
        From worker 5:       * core
        From worker 2:       * linalg1
        From worker 4:       * linalg3
        From worker 8:       * strings
        From worker 6:       * keywordargs
        From worker 7:       * numbers
        From worker 9:       * collections
        From worker 6:       * hashing
        From worker 6:       * remote
        From worker 6:       * iobuffer
        From worker 6:       * arrayops
        From worker 9:       * simdloop
        From worker 5:       * blas
        From worker 8:       * fft
        From worker 9:       * dsp
        From worker 8:       * sparse
        From worker 9:       * bitarray
        From worker 5:       * random
        From worker 5:       * math
        From worker 5:       * functional
        From worker 5:       * bigint
        From worker 7:       * sorting
        From worker 5:       * statistics
        From worker 8:       * spawn
        From worker 6:       * backtrace
        From worker 6:       * priorityqueue
        From worker 7:       * arpack
        From worker 6:       * file
        From worker 8:         [stdio passthrough ok]
        From worker 4:       * suitesparse
        From worker 5:       * version
        From worker 5:       * resolve
        From worker 4:       * pollfd
exception on 8: ERROR: test failed: readall(@cmd "\$exename -f -e 'println(STDERR,\"Hello World\")'" .> @cmd "cat") == "Hello World\n"

[mbauman]

It's failing because that AVX warning is getting printed on every invocation of Julia, and the test in spawn.jl is checking that only "Hello World\n" gets printed (which is very important if you're redirecting the output of some big script to, e.g., a CSV file to be read later). I believe that the warning should be properly hidden by default in the new OpenBLAS release candidate (v0.2.9.rc2).

See this discussion on julia-users and issue #6728.

[andrioni]

AFAIR, I also tested it with 0.2.9.rc2 (targeting Sandy Bridge, which is the default detected) and had the same issue, but let me retry.

Another solution would be to always default to Nehalem in paravirtualized EC2 boxes (since their Xen PV solution doesn't support AVX, while their HVM one does), but this is probably more relevant to OpenBLAS than Julia.

[andrioni]

Apparently I was getting the wrong one by mistake, so everything should be fine after the update.

@xianyi Is there actually a way to get from Julia/the shared library which arch it is targeting at runtime and which version is linked?